DETERMINATION OF THE NONINDUCTIVE CURRENT PROFILE IN TOKAMAK PLASMAS

The noninductive part of the measured current profile has been determi ned for DIII-D plasmas. A technique for determining the flux surface a verage of the quantity E . B and a model for the resistivity separates the current profile into inductive and noninductive portions. Analysi s shows directly that neoclassical resistivity is adequate to explain the experimental observations, while Spitzer resistivity is not, and t hat a large noninductive current exists in plasmas for which large neu tral beam current drive and pressure driven bootstrap currents are exp ected.